Overview Information

Black tea is a product made from the Camellia sinesis plant. The aged leaves and stems are used to make medicine. Green tea, which is made from fresh leaves of the same plant, has some different properties.

How does it work?

Black tea contains 2% to 4% caffeine, which affects thinking and alertness, increases urine output, and may reduce the symptoms of Parkinson's disease. It also contains antioxidants and other substances that might help protect the heart and blood vessels.

Uses & Effectiveness?

Likely Effective for

Mental alertness. Drinking black tea and other caffeinated beverages throughout the day helps to keep people alert, even after extended periods without sleep.

Possibly Effective for

Hardening of the arteries (atherosclerosis). Early research shows that people who drink black tea seem to have a reduced risk of having their arteries become hardened. This link is stronger in women than men.

Heart attacks. Some research shows that people who drink black tea have a lower risk of having a heart attack. Also, people who have been drinking black tea for at least a year before having a heart attack seem to be less likely to die after having a heart attack.

Brittle bones (osteoporosis). Early research shows that older women who drink more black tea seem to have stronger bones. Drinking more black tea also seems to be linked with a lower risk of hip fracture in older men and women.

Ovarian cancer. Women who regularly drink tea, including black tea or green tea, appear to have a lower risk of developing ovarian cancer compared to women who never or rarely drink tea.

Parkinson's disease. Some research shows that people who drink caffeinated beverages such as coffee, tea, and cola have a lower risk of Parkinson's disease. The lower risk seems to be directly related to the dose of caffeine in men but not women. Drinking black tea also appears to be linked with a reduced risk of Parkinson's disease among people who smoke cigarettes.

Possibly Ineffective for

Breast cancer. People who drink black tea do not seem to have a lower risk of breast cancer.

Colon and rectal cancer. Some early research suggests that drinking black or green tea might be linked with a lower risk of colon and rectal cancer. However, most research shows that drinking tea is not linked with a lower risk of colon and rectal cancer. In fact, some early research suggests that drinking higher amounts of black tea might be linked with an increased risk of colon and rectal cancer.

Diabetes. Early research suggests that taking an extract of black and green tea does not improve HbA1C levels in people with diabetes. HbA1C is a measure of blood sugar control. Other early research suggests that drinking at least one cup of black tea per day is not linked with a lower risk of developing type 2 diabetes in Japanese adults.

Stomach cancer. Some early research suggests that drinking black or green tea might be linked with a lower risk of stomach cancer. However, most research shows that people who drink black or green tea do not have a lower risk. In fact, some early research suggests that drinking higher amounts of black tea might be linked with an increased risk of stomach cancer.

High cholesterol. Some research shows that black tea might reduce total cholesterol and low-density lipoprotein (LDL or “bad”) cholesterol in people with normal or high cholesterol levels. However, most research shows that drinking black tea does not have these effects.

High blood pressure. Some early research suggests that people who regularly drink green or black tea have a lower risk of having high systolic blood pressure, which is the top number of a blood pressure reading. However, most research shows that drinking black tea does not reduce blood pressure in people with normal or high blood pressure.

Insufficient Evidence for

Bladder cancer. Some early research suggests that people who drink black or green tea might have a lower risk of urinary tract cancers. However, other research shows that drinking black tea is not linked with a reduced risk of bladder cancer.

Heart disease. Some early research suggests that people who regularly drink black tea have a lower risk of developing heart disease. However, other research suggests that drinking black tea is linked with an increased risk of heart disease becoming worse or causing death.

Cavities. Early research suggests that rinsing with a black tea extract might prevent cavities.

Kidney cancer. Early research suggests that people who drink more black or green tea have a higher risk of developing kidney cancer.

Lung cancer. Green tea and black tea contain chemicals called phytoestrogens. Some research shows that men who get more phytoestrogens in their diet have a lower risk of developing lung cancer than men who do not get these chemicals. However other early research suggests that drinking black tea is not linked with a reduced risk of lung cancer and may even be linked with an increased risk.

Mouth cancer. Early research shows that black tea might help prevent mouth cancer in patients with lesions in the mouth that may turn into cancer.

Pancreatic cancer. Some early research suggests that drinking black tea is linked with a reduced risk of pancreatic cancer risk. However, other research shows conflicting results.

Prostate cancer. Early evidence suggests that drinking black tea is linked with a reduced risk of prostate cancer.

Stress. Early research suggests that drinking black tea for 6 weeks does not improve blood pressure, heart rate, or feelings of stress ratings while performing stressful tasks.

Stroke. Black tea contains chemicals called flavonoids. Early research suggests that eating a diet that contains flavonoids is linked with a lower risk of stroke.

Side Effects & Safety

Drinking moderate amounts of black tea is LIKELY SAFE for most adults.

Drinking too much black tea, such as more than five cups per day, is POSSIBLY UNSAFE. High amounts of black tea can cause side effects due to the caffeine in black tea. These side effects can range from mild to serious and include headache, nervousness, sleep problems, vomiting, diarrhea, irritability, irregular heartbeat, tremor, heartburn, dizziness, ringing in the ears, convulsions, and confusion. Also, people who drink black tea or other caffeinated beverages all the time, especially in large amounts, can develop psychological dependence.

Drinking very high amounts of black tea containing more than 10 grams of caffeine is LIKELY UNSAFE. Doses of black tea this high might cause death or other severe side effects.

Caffeine is PROBABLY SAFE in children in amounts commonly found in foods.

Special Precautions & Warnings:

Children: Black tea is POSSIBLY SAFE when taken by mouth by children in amounts commonly found in foods.

Pregnancy and breast-feeding: If you are pregnant or breast-feeding, drinking black tea in small amounts is POSSIBLY SAFE. Do not drink more than 3 cups a day of black tea. This amount of tea provides about 200 mg of caffeine. Consuming more than this amount during pregnancy is POSSIBLY UNSAFE and has been linked to an increased risk of miscarriage, increased risk of sudden infant death syndrome (SIDS), and other negative effects, including symptoms of caffeine withdrawal in newborns and lower birth weight.

If you are breast-feeding, drinking more than 3 cups a day of black tea is POSSIBLY UNSAFE and might cause your baby to become more irritable and have more bowel movements.

Anemia: Drinking black tea may make anemia worse in people with iron deficiency.

Anxiety disorders: The caffeine in black tea might make these conditions worse.

Bleeding disorders: There is some reason to believe that the caffeine in black tea might slow blood clotting, though this hasn’t been shown in people. Use caffeine cautiously if you have a bleeding disorder.

Heart problems: Caffeine in black tea can cause irregular heartbeat in certain people. If you have a heart condition, use caffeine with caution.

Diabetes: The caffeine in black tea might affect blood sugar. Use black tea with caution if you have diabetes.

Diarrhea: Black tea contains caffeine. The caffeine in black tea, especially when taken in large amounts, can worsen diarrhea.

Seizures: Black tea contains caffeine. There is a concern that high doses of caffeine might cause seizures or decrease the effects of drugs used to prevent seizures. If you have ever had a seizure, don’t use high doses of caffeine or caffeine-containing supplements such as black tea.

Hormone-sensitive condition such as breast cancer, uterine cancer, ovarian cancer, endometriosis, or uterine fibroids: Black tea might act like estrogen. If you have any condition that might be made worse by exposure to estrogen, don’t use black tea.

High blood pressure: The caffeine in black tea might increase blood pressure in people with high blood pressure. However, this doesn't seem to occur in people who drink black tea or other caffeinated products regularly.

Irritable bowel syndrome (IBS): Black tea contains caffeine. The caffeine in black tea, especially when taken in large amounts, can worsen diarrhea and might worsen symptoms of IBS.

Brittle bones (osteoporosis): Drinking caffeinated black tea can increase the amount of calcium that is flushed out in the urine. This might weaken bones. Don’t drink more than 300 mg of caffeine per day (approximately 2-3 cups of black tea). Taking extra calcium may help to make up for calcium losses. Older women who have a genetic condition that affects the way they use vitamin D, should use caffeine with caution.

Overactive bladder: The caffeine in black tea might increase the risk of developing an overactive bladder. Also, black tea might increase symptoms in people who already have an overactive bladder. Black tea should be used with caution in these people.

Interactions?

Moderate Interaction

Be cautious with this combination

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Adenosine (Adenocard) interacts with BLACK TEA

Black tea contains caffeine. The caffeine in black tea might block the affects of adenosine (Adenocard). Adenosine (Adenocard) is often used by doctors to do a test on the heart. This test is called a cardiac stress test. Stop drinking black tea or other caffeine-containing products at least 24 hours before a cardiac stress test.

Antibiotics (Quinolone antibiotics) interacts with BLACK TEA

The body breaks down caffeine to get rid of it. Some antibiotics might decrease how quickly the body breaks down caffeine. Taking these antibiotics along with black tea can increase the risk of side effects including jitteriness, headache, increased heart rate, and other side effects.<br /><br />
Some antibiotics that decrease how quickly the body breaks down caffeine include ciprofloxacin (Cipro), enoxacin (Penetrex), norfloxacin (Chibroxin, Noroxin), sparfloxacin (Zagam), trovafloxacin (Trovan), and grepafloxacin (Raxar).

Cimetidine (Tagamet) interacts with BLACK TEA

Black tea contains caffeine. The body breaks down caffeine to get rid of it. Cimetidine (Tagamet) can decrease how quickly your body breaks down caffeine. Taking cimetidine (Tagamet) along with black tea might increase the chance of caffeine side effects including jitteriness, headache, fast heartbeat, and others.

Clozapine (Clozaril) interacts with BLACK TEA

The body breaks down clozapine (Clozaril) to get rid of it. The caffeine in black tea seems to decrease how quickly the body breaks down clozapine (Clozaril). Taking black tea along with clozapine (Clozaril) can increase the effects and side effects of clozapine (Clozaril).

Dipyridamole (Persantine) interacts with BLACK TEA

Black tea contains caffeine. The caffeine in black tea might block the affects of dipyridamole (Persantine). Dipyridamole (Persantine) is often used by doctors to do a test on the heart. This test is called a cardiac stress test. Stop drinking black tea or other caffeine containing products at least 24 hours before a cardiac stress test.

Disulfiram (Antabuse) interacts with BLACK TEA

The body breaks down caffeine to get rid of it. Disulfiram (Antabuse) can decrease how quickly the body gets rid of caffeine. Taking black tea (which contains caffeine) along with disulfiram (Antabuse) might increase the effects and side effects of caffeine including jitteriness, hyperactivity, irritability, and others.

Ephedrine interacts with BLACK TEA

Stimulant drugs speed up the nervous system. Black tea contains caffeine. Caffeine and ephedrine are both stimulant drugs. Taking black tea along with ephedrine might cause too much stimulation and sometimes serious side effects and heart problems. Do not take caffeine containing products and ephedrine at the same time.

Estrogens interacts with BLACK TEA

The body breaks down the caffeine in black tea to get rid of it. Estrogens can decrease how quickly the body breaks down caffeine. Taking estrogen pills and drinking black tea can cause jitteriness, headache, fast heartbeat, and other side effects. If you take estrogen pills limit your caffeine intake.<br /><br />
Some estrogen pills include conjugated equine estrogens (Premarin), ethinyl estradiol, estradiol, and others.

Fluvoxamine (Luvox) interacts with BLACK TEA

The body breaks down the caffeine in black tea to get rid of it. Fluvoxamine (Luvox) can decrease how quickly the body breaks down caffeine. Taking caffeine along with fluvoxamine (Luvox) might cause too much caffeine in the body, and increase the effects and side effects of caffeine.

Lithium interacts with BLACK TEA

Your body naturally gets rid of lithium. The caffeine in black tea can increase how quickly your body gets rid of lithium. If you take products that contain caffeine and you take lithium, stop taking caffeine products slowly. Stopping caffeine too quickly can increase the side effects of lithium.

Medications for depression (MAOIs) interacts with BLACK TEA

The caffeine in black tea can stimulate the body. Some medications used for depression can also stimulate the body. Drinking black tea and taking some medications for depression might cause too much stimulation of the body and serious side effects including fast heartbeat, high blood pressure, nervousness, and others.<br /><br />
Some of these medications used for depression include phenelzine (Nardil), tranylcypromine (Parnate), and others.

The stimulant effects of the caffeine in black tea can block the sleep-producing effects of pentobarbital.

Phenylpropanolamine interacts with BLACK TEA

The caffeine in black tea can stimulate the body. Phenylpropanolamine can also stimulate the body. Taking caffeine and phenylpropanolamine together might cause too much stimulation and increase heartbeat, blood pressure, and cause nervousness.

Riluzole (Rilutek) interacts with BLACK TEA

The body breaks down riluzole (Rilutek) to get rid of it. Drinking black tea can decrease how quickly the body breaks down riluzole (Rilutek) and increase the effects and side effects of riluzole.

Stimulant drugs interacts with BLACK TEA

Stimulant drugs speed up the nervous system. By speeding up the nervous system, stimulant medications can make you feel jittery and speed up your heartbeat. The caffeine in black tea can also speed up the nervous system. Drinking black tea along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Avoid taking stimulant drugs along with black tea.<br /><br />
Some stimulant drugs include diethylpropion (Tenuate), epinephrine, phentermine (Ionamin), pseudoephedrine (Sudafed), and many others.

Theophylline interacts with BLACK TEA

Black tea contains caffeine. Caffeine works similarly to theophylline. Caffeine can also decrease how quickly the body gets rid of theophylline. This might cause increased effects and side effects of theophylline.

Verapamil (Calan, Covera, Isoptin, Verelan) interacts with BLACK TEA

The body breaks down the caffeine in black tea to get rid of it. Verapamil (Calan, Covera, Isoptin, Verelan) can decrease how quickly the body gets rid of caffeine. Drinking black tea and taking verapamil (Calan, Covera, Isoptin, Verelan) can increase the risk of side effects for caffeine including jitteriness, headache, and an increased heartbeat.

Warfarin (Coumadin) interacts with BLACK TEA

Warfarin (Coumadin) is used to slow blood clotting. Large amounts of black tea might decrease how well warfarin (Coumadin) slows blood clotting. Decreasing the how well warfarin (Coumadin) slows blood clotting might increase the risk of clotting. It is unclear why this interaction might occur. Be sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.

Minor Interaction

Be watchful with this combination

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Alcohol interacts with BLACK TEA

The body breaks down the caffeine in black tea to get rid of it. Alcohol can decrease how quickly the body breaks down caffeine. Taking black tea along with alcohol might cause too much caffeine in the bloodstream and caffeine side effects including jitteriness, headache, and fast heartbeat.

Birth control pills (Contraceptive drugs) interacts with BLACK TEA

The body breaks down the caffeine in black tea to get rid of it. Birth control pills can decrease how quickly the body breaks down caffeine. Taking black tea along with birth control pills can cause jitteriness, headache, fast heartbeat, and other side effects.<br /><br />
Some birth control pills include ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone (Ortho-Novum 1/35, Ortho-Novum 7/7/7), and others.

Fluconazole (Diflucan) interacts with BLACK TEA

Black tea contains caffeine. The body breaks down caffeine to get rid of it. Fluconazole (Diflucan) might decrease how quickly the body gets rid of caffeine. This could cause caffeine to stay in to body too long and increase the risk of side effects such as nervousness, anxiety, and insomnia.

Coffee contains chemicals called tannins. Tannins can bind to many medications and decrease how much medicine the body absorbs. To avoid this interaction avoid coffee 1 hour before and 2 hours after taking medications for depression called tricyclic antidepressants.<br /><br />
Some medications for depression include amitriptyline (Elavil) or imipramine (Tofranil, Janimine).

Black tea contains caffeine. The body breaks down caffeine to get rid of it. Mexiletine (Mexitil) can decrease how quickly the body breaks down caffeine. Taking Mexiletine (Mexitil) along with black tea might increase the caffeine effects and side effects of black tea.

The body breaks down the caffeine in black tea to get rid of it. Terbinafine (Lamisil) can decrease how quickly the body gets rid of caffeine and increase the risk of side effects including jitteriness, headache, increased heartbeat, and other effects.

For preventing Parkinson's disease: men drinking 421-2716 mg of total caffeine (approximately 5-33 cups of black tea) daily have the lowest risk of developing Parkinson's disease, when compared to other men. However, men who drink as little as 124-208 mg of caffeine (approximately 1-3 cups of black tea) daily also have a significantly lower chance of developing Parkinson's disease. In women, moderate caffeine intake (1-4 cups of black tea) per day seems to be best.

Institute of Medicine. Caffeine for the Sustainment of Mental Task Performance: Formulations for Military Operations. Washington, DC: National Academy Press, 2001. Available at: http://books.nap.edu/books/0309082587/html/index.html.

CONDITIONS OF USE AND IMPORTANT INFORMATION:
This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.